1. Field of the Invention
This invention relates to novel pyrone-3-carboxamide compounds and herbicidal compositions thereof, and to novel growth regulating agents.
2. Description of the Prior Art
Certain compounds belonging to 4-oxo-4H-pyran-3-carboxamides have been mentioned in the literature.
That is, it has been known that the treatment of o-haloacetoanilides (2-chloro, 2-bromo, 2,4-dichloro or 2,5-dichloro compound) with polyphosphoric acid for an hour at 140.degree. C. gives the corresponding halogen derivatives of 2,6-dimethyl-4-oxo-N-phenyl-4H-pyran-3-carboxamide (A. K. Mallams and S. S. Islaelstam: J. Org. Chem., 29, 3548 (1964); A. K. Mallams: J. Org. Chem., 29, 3555 (1964)). This method using polyphosphoric acid was applied on other acetoacetoanilides (2-fluoro, 2-piperidino, 2-hexahydroazepinyl, 2-morpholino, 2-pyrrolidinyl or the like) or benzoylacetoanilides to yield the corresponding 4-oxo-4H-pyran-3-carboxamide compounds [R. Garner and H. Suschitzky: J. Chem. Soc. (C), 186 (1966)].
Also, 4-oxo-N-2,6-triphenyl-4H-pyran-3-carboxamide was obtained by treating benzoylacetoanilide with succinyl dichloride [Zankowska-Jasinsca. W. et al.: Zesz. Nawk. Uniw. Jagiellon., Pr. Chem. 1980, 25, 7; ibid 1976, 21, 141].
The formation of 2,6-dimethyl-N-(4-nitrophenyl)-4-oxo-4H-pyran-3-carboxamide was identified as the reaction product between p-nitroaniline and diketene [(Kato and Kubota; Yakugakuzassi, 87, 1212 (1967)]. Also, N-(2-chlorophenyl)-2,6-dimethyl-4-oxo-4H-pyran-3-carboxamide was obtained by treating 2,6-dimethyl-4-oxo-4H-pyran-3-carboxylic acid with thionyl chloride followed by the reaction with o-chloroaniline, or by heating p-nitrophenyl ester of 2,6-dimethyl-4-oxo-4H-pyran-3-carboxylic acid and o-chloroaniline for 4.3 hours at 110.degree. C. [Toda: Yakugakuzassi, 87, 1351 (1967)]. This literature disclosed pyrone-3-carboxamide compounds which were obtained by the reaction of 2-aminotroponesor 4-aminotropolones with diketene.
Also, in Japanese Patent Publication No. 45(1970)-31663, it disclosed a process for preparing 2,6-dimethyl-4-oxo-4H-pyran-3-carboxamides which comprises reacting isocyanates and diketene in the presence of an acid catalyst, and specifically disclosed in the working examples 2,6-dimethyl-4-oxo-N-phenyl-4H-pyran-3-carboxamide, 2,6-dimethyl-N-(2-methylphenyl)-4-oxo-4H-pyran-3-carboxamide, N-(2-chlorophenyl)-2,6-dimethyl-4-oxo-4H-pyran-3-carboxamide, 2,6-dimethyl-N-(2-nitrophenyl)-4-oxo-4H-pyran-3-carboxamide, N-(2,5-dichlorophenyl)-2,6-dimethyl-4-oxo-4H-pyran-3-carboxamide, 2,6-dimethyl-N-(3-nitrophenyl)-4-oxo-4H-pyran-3-carboxamide and 2,6-dimethyl-N-(4-methylphenyl)-4-oxo-4H-pyran-3-carboxamide.
Further, 2,6-dimethyl-4-oxo-N-phenyl-4H-pyran-3-carboxamide, N-(4-methoxyphenyl)-2,6-dimethyl-4-oxo-4H-pyran-3-carboxamide and N-(4-chlorophenyl)-2,6-dimethyl-4-oxo-4H-pyran-3-carboxamide have been disclosed as the reaction products between 3-morpholinocrotonanilide compounds and diketene [Kato et al: Yakugakuzassi, 101, 43 (1981)].
In addition, there have been reports about pyrone-3-carboxamide compounds which correspond to aminotropones [H. Toda and S. Seto: Chem. Pharm. Bull., 19, 1477 (1971)], aminopyridines [T. Kato et al: Chem. Pharm. Bull., 20, 133 (1972); ibid. 28, 2129 (1980); H. L. Yale et al: J. Heterocyclic Chem., 14, 637 (1977)] and 2-amino-1,3,4-thiadiazoles [R. F. Lauer et al: J. Heterocyclic Chem., 13, 291 (1976)], respectively.
It was disclosed in the above mentioned Japanese Patent Publication No. 45(1970)-31663 that 2,6-dimethyl-4-oxo-4H-pyran-3-carboxamides have utility as agricultural drugs such as a control agent of sheath blight of rice, nematicide or acaricide, or drugs such as an antiviral agent or the like, but did not disclose any data supporting such utility.
There have been no reports on the pyrone-3-carboxamide compounds represented by the formula (I) of the present invention (set forth below), nor has there been any suggestion regarding possible plant growth inhibitory activity.